Device, system and method for processing a sample

ABSTRACT

A device for processing a sample comprises a blister defined by first and second walls. The first wall is flexible allowing the blister to be divided into one or more sealed regions by an external pressure applied to a portion of the first wall. The external pressure is applied in the form of a 2-dimensional shape to form a sealed region having that shape.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application that claims the benefit of and priorityto related U.S. patent application Ser. No. 12/673,939, filed on Mar. 3,2011, which application was filed under 35 U.S.C. 371 and claims thebenefit of and priority to International Patent ApplicationPCT/GB2008/002802 filed Aug. 18, 2008 published in the English languageas WO2009/024773, which application claims the benefit of and priorityto GB application number GB0814550.0, filed Aug. 8, 2008 and GBapplication number GB0716156.5, filed on Aug. 17, 2007. All of the aboveapplications are incorporated by reference herein in their entirety.

The invention relates to devices, a system and a method for theprocessing of a sample. In particular the invention relates toin-the-field and on-site analysis of nucleic acid or genetic material ina biological or environmental sample.

BACKGROUND

The importance of nucleic add testing (NAT) has become increasinglyevident during the last decade for many purposes such as screening anddiagnosis of infectious diseases and genetic disorders, testing fordisease susceptibility, therapy monitoring, and improving the safety ofblood supplies. NAT combines the advantages of direct and highlysequence-specific detection of the genome of an infectious agent with ananalytic sensitivity that is several orders of magnitude greater thanthat of immune-based tests, or virus isolation and self culture methods.Due to the high sensitivity of NAT, its use in blood banks reduces therisk of infectious agent transmission during the period betweeninfection and seroconversion, of infection with immunovariant viruses,of immunosilent or occult carriage. NAT-based assays consist of threebasic steps: extraction of nucleic acid, genome amplification mediatedby procedures such as (RT)-PCR; strand-displacement amplification (SDA)and transcription-based amplification system TAS (Guatelli et al., Proc.Natl. Acad. Sci. 87: 1874-1878 (1990); Compton, Nature 350: 91-92(1991)), and amplicon detection.

Currently available NAT assays are complex and entail multi-stepprocedures that require highly trained personnel and specialisedfacilities. They require cold-chain transport and storage of reagents, ahigh investment cost for instruments, high running costs for reagents,and regular maintenance support. All of these restrict the use of NATonly to specialized well-equipped and technically advanced laboratories.Correspondingly, current NAT assay design is unsuitable for near-patientand field-testing e.g. physician's office, community-based clinics,emergency rooms, battlefield surgery units or point-of care healthcentres, district hospitals and inner-city clinics in theresource-limited settings of developing countries. These includepredominantly countries of Africa, Asia, and Latin America with a highprevalence of infectious diseases.

An essential requirement for assays based on nucleic acid amplificationis protection from amplicon contamination, currently solved by workingin specialized laboratories using dedicated spaces for samplepreparation, amplification and detection. This approach is notapplicable for field-testing, near-patient testing and inresource-limited settings.

SUMMARY OF INVENTION

The invention provides devices, a system, a method, and a machineaccording to the appended independent claims, to which reference shouldnow be made. Preferred or advantageous features of the invention in itsvarious embodiments and aspects are defined in dependant sub-claims.

Accordingly, in a first aspect the invention may provide a device forthe processing of a sample comprising, a blister defined between firstand second walls wherein the first wall is flexible such that theblister can be divided into one or more sealed regions by an externalpressure applied to a portion of the first wall that urges the firstwall towards the second wall. Preferably, the pressure is applied in theform of a two dimensional shape to form a sealed region in that shape.

It is preferable that the entire boundary or perimeter of at least onesealed region is formed by the external pressure.

The external pressure is preferably exerted by application of one ormore shaped tools or platens to an outer surface of the portion of thefirst wall to urge it towards the second wall. At least one platen ispreferably in the form of a two dimensional shape to form a sealedregion having that shape.

Advantageously the platen may apply pressure corresponding to theperimeter or border of a two dimensional shape to form a sealed regionhaving that shape.

The device may have first and second sealed regions having first andsecond perimeters, the regions being formed by application of pressurefrom first and second shaped platens, the first sealed region beingenclosed within the perimeter of the second sealed region.

Shaped tools or platens may be actuated by a machine for automaticprocessing of the sample. Advantageously, this allows the sample to beprocessed within a single blister yet still undergo a complex processingprotocol. The blister may, for example, contain a number of processingreagents retained at different locations within the blister. The blistercan then be divided by the application of localised external pressureinto one or more sealed regions, preferably with different sealedregions corresponding to the location of different processing reagents.The removal of the external pressure may result in the loss of a sealdefining a sealable region. For example, a blister that has been dividedby the application of one or mom shaped platens into three separatesealed regions may revert to a single blister having a single internalspace or cavity once the platens have all been removed.

It is preferable that, once a sample has been introduced into theblister, all further sample processing steps are carried oat within theblister. This may reduce the chances of contamination of the sample bycontaminating elements in the external environment. This may also reducethe risk that the external environment, for example, in the vicinity ofa processing facility that uses the device, will be contaminated by thesample within the blister.

The device may be in the form of a card, cartridge or insert forintroduction into a machine, for example into a port or docking stationthat places the device at a predetermined position in the machine, forautomatically processing the sample according to predeterminedprocessing steps. It is advantageous, therefore, that any objectcontained within the blister, for example an object for use in aprocessing step, is retained at a predetermined location within theblister. This may allow an automated processing means to be positionedin view of the predetermined location of the object.

Retaining an object at a location within the blister is particularlyadvantageous where the blister contains more than one object,particularly more than one different type of object. For example, theblister may contain more than one different type of processing reagent,each different type being located at a different predetermined locationwithin the blister. An object may be a dried reagent or an object may bea sachet of liquid, for example a sachet containing a liquid processingreagent or a sachet containing a processing buffer, it is particularlyadvantageous that these different types of object can be retained atdifferent predetermined locations within the blister even though theblister itself may define a single connected volume when delivered to atest site. Advantageously, a seal can be formed around a retained objectby application of pressure from a shaped platen thereby forming a sealedregion containing the object.

A device according this first aspect of the invention is, advantageouslysimple in structure and therefore easy to produce. Many prior artdevices for processing samples involve complex patterns of channels andchambers to form complex flow paths. These devices need to bemanufactured with these complex patterns defined by permanent seals,which may increase the cost of each device.

In the device of the present invention one or more sealed regions areformed within the blister during processing. Therefore, these sealedregions do not need to be formed during manufacture of the device andthe device as produced has a simpler structure.

Some prior art devices make use of temporary, or frangible seals toisolate different sealed chambers. Generally, pressure is applied tobreak such a seal and allow communication between two different regionsof the device. Breaking such frangible seals may be unreliable, however,particularly when the regions they separate only contain low volumes ofmaterial, for example 50 microliters or lass of a liquid sample.

The use of an external pressure to form a seal as in the presentinvention advantageously overcomes the problem of unreliable frangibleseals. As the pressure is applied a seal can be formed and this seal isremoved when the external pressure is removed.

The use of an external pressure to form the entire boundary or perimeterof a sealed region has a further advantage. If a sealed region is formedfrom a combination of permanent seals and pressure seals (as may happen,for example, if a channel defined by a permanent weld or heat seal isclosed by an external pressure across the channel) the integrity of theseal may be low. The applicants have discovered that when placing apressure seal over a blister or channel a capillary fluid path mayremain at the interface between the pressure seal end the heat seal.Even when this capillary flow path only allows a small volume of liquidto pass, the seal is compromised. One deleterious effect that may occurwhen a small amount of liquid is leaked is the unwanted rehydration ofreagents held in adjacent sealed regions. The applicants have found thatthe use of a pressure seal to form the entire boundary of a sealedregion within the blister eliminates this problem.

In a second aspect the invention provides a device for processing asample comprising a blister defined by, or between, first and secondwalls, in which an object is retained at a predetermined location withinthe blister. The blister defines a space that is sealed from theexternal environment, within which at least some of the processing stepsfor processing the sample may be performed. The object is for use in atleast one of the processing stops.

In a third aspect the invention may provide a device for the processingof a sample comprising a blister defined between first and second wallsin which the blister contains both solid and liquid objects, orprocessing reagents. The blister (as in all aspects of the invention)may provide a processing space that is sealed from the externalenvironment and the blister may, therefore, contain reagents such asfreeze dried or lyophilised reagents and liquid reagents or buffers.Preferably the liquid processing reagents or buffers are contained inone or mere sachets and preferably all of the reagents are retained atpredetermined locations within the blister.

Many sample processing protocols involve liquid reagents (in thiscontext for brevity the term reagent is taken to include substances suchas buffers or solvents that may be required during processing steps).The existence of both solid and liquid processing reagents within asingle blister that is sealed from the environment reduces the number ofelements that need to fee introduced to the blister on site (i.e. onlythe sample, or a pre-processed sample, may need to be introduced). Thisfurther reduces the chances of contamination during or resulting fromprocessing the sample.

In a fourth aspect the invention may provide a device for the processingof a sample comprising a blister defined between first and second wallswherein the blister contains a sachet of liquid, the sachet having afrangible or breakable seal that allows its liquid to be released intothe blister on the application of a localised external pressure to thesachet. The term sachet may include any suitable liquid container thatretains the liquid contents and releases them when the sachet is brokenopen or bursts on the application of a predetermined pressure or force.It is advantageous to perform the processing of a sample within a singleblister that is sealed from the external environment, in many processingdevices where sealing from the environment is an important issue, waysmust be found to introduce liquid processing reagents where these arerequired for a particular processing protocol. By including a sachetcontaining the liquid within a sealed processing blister the risks ofcontamination when introducing a liquid reagent are reduced.Furthermore, assembly or production of the device may be made mucheasier as a sachet of liquid is a discrete, tangible and dry object.Thus, a sachet may be considerably easier to handle during assemblythan, say, a volume of liquid that has to be loaded into a processingdevice without having its own containment. This advantage isparticularly clear when it is borne in mind that the device needs to beassembled in very clean, sterile conditions.

Preferably, a wall of the blister is flexible such that the liquidwithin the sachet may be deployed by the application of an externalpressure to the sachet through the flexible wall. Thus, the liquidwithin the sachet may be retained within the sachet, and therefore awayfrom the sample and any processing steps being carried out within theblister, until the liquid is required.

In a fifth aspect the invention may provide a device for the processingof a sample comprising a blister defined between first and second wallsand having a vacuum port that allows air or gas to be withdrawn from theblister.

A vacuum port may simply be a port sealed by a resilient septum, throughwhich a syringe may be inserted as a moans to apply a vacuum.

There may be a number of advantages to applying a vacuum to a blisterfor processing a sample. If the blister has a wall that is flexible, thewithdrawal of air may create a vacuum within the blister and urge thefirst and second walls of the blister together. Advantageously, this mayassist in retaining any objects placed within the blister atpredetermined locations.

Where the blister can be divided during processing into one or moresealed regions, as described above, then a vacuum may aid in thetransfer of the sample between these regions as the seals are removed. Avacuum may also in such circumstances aid mixing of the sample bycreating turbulence when a region that is at atmospheric pressure isopened up by the removal of a seal to a region that is at a lower thanatmospheric pressure.

Removal of air may also foe important for performing processingprotocols that, for example, are more effectively performed in theabsence of oxygen and/or humidity.

In its broadest sense the invention provides a device for processing ofa sample comprising a blister or sealed enclosure defined by or betweenfirst and second walls. The various different characterising featuresdefining aspects of the invention as described above may exist in anypermutation or combination within a single device according to theinvention. The following preferred features relate to a device accordingto any aspect described herein.

Preferably the first waif of the blister is flexible such that alocalised external pressure urging a portion of the first wall towardsthe second wall can produce a localised seal. This may allow the blisterto be divided during processing into two or mere temporarily sealedregions for carrying out different processing steps. Preferably the sealopens when the localised external pressure is removed. Advantageously,such seals may be formed and opened multiple times if required for aparticular processing protocol.

It may be advantageous that an object is retained at a predeterminedlocation within the blister. Thus, when manufacturing a device thatincludes an object for use in processing of a sample, such as a driedreagent or a sachet of liquid, such objects can be placed within theblister on manufacture. One method of locating an object has alreadybeen mentioned above, i.e. the application of a vacuum to the blister todraw in a wall of the blister against the object, thereby retaining theobject at a predetermined location within the blister.

An object, such as a dried reagent or a sachet of liquid, may beretained at a location within the blister by mechanical locating means,such as dimples or recesses defined in the first wall or the second wallof the blister, or in any other appropriate manner. Location of objectswithin the blister is particularly preferable where the processing ofthe sample involves forming the blister into more than one temporarilysealed chamber by the application of external pressures as theboundaries between the chambers may then be positioned so that theobjects are positioned in desired chambers.

Preferably the device comprises a sample introduction port to allow theintroduction of a sample into the blister. The port could be a portextending through the first wall or the second wall of the blister orcould be a port that extends into the blister at a join between the twowalls. Such a sample introduction port may comprise a resilient septumthat allows introduction of a sample using a hypodermic needle.

The blister may be defined by or between a first wall that is a flexiblefilm and a second wall that is a substantially rigid base plate, theflexible film being joined to the base plate to form a blister. The useof a base plate may be advantageous where the device is a card orcartridge for introduction into an automatic processing machine. Thebase plate may provide support for the blister, particularly where theblister is to be subjected to external pressures.

Both first and second walls may be a flexible film. In this situationthe device may further comprise a frame to support the second wall.

The device may comprise a gasket disposed within the blister. Whom thereis a gasket, localised pressure urging a portion of the first walltowards the second wall may sandwich the gasket between the first walland second wall to form a localised seal. Preferably the gasket is amaterial that is disposed on the first or second wall within the blisterto define one or more sealable regions within the blister.

Where the second wall of the blister is a base plate it is preferablethat any gasket material be a material softer than the base plate thatis disposed on the base plate within the blister.

The gasket may define locating dimples or recesses.

As the first wall is flexible and the device may contain reagents, itmay be advantageous that the device includes a cover for protecting thedevice during transit or during handling. Such a cover may be removableor may be hinged, for example to a base plate of the device if a baseplate is present. Any cover may be simply removable to allow a sample tobe processed using the device. Alternatively the cover may retract oropen on placing the device into a processing machine.

A cover for a device according to an aspect of the invention maycomprise structures such as ribs that exert an external pressure to aportion or portions of the first wall, when the cover is closed over thedevice, to form temporarily partitions or sealed regions within theblister. These partitions or regions may advantageously help to maintainobjects such as reagents in predetermined positions within the blisterduring transportation and storage. This may be of particular advantagewhere an object, such as a freeze-dried reagent, becomes damaged orfragmented during transit. The use of a cover shaped to partition orseal regions of the blister containing objects allows all fragments of adamaged object to be maintained in a predetermined location such that avalid processing may still be earned out (i.e. the volume of a reagentin a predetermined location is not diminished due to fragmented portionsmigrating to a different region of the blister.)

Preferably the blister can be divided into one or more sealed regions byapplication of one or more shaped platens to urge one or more portionsof the first wall towards the second wall. This allows the temporaryformation of more than one sealed chamber within the sealed blisterthereby allowing complex processing protocols to take place within asingle blister. Particularly preferably the sealed regions can be sealedand unsealed sequentially to allow the sample and/or reagents within theblister to pass between the regions in a predetermined manner. Forexample, one or more of the sealed regions may contain a processingreagent or more than one processing reagents and removal of the sealsforming the sealed regions may allow the sample to contact theprocessing reagent or reagents, either by movement of the sample towardsthe reagent or by movement of the reagent towards the sample.

Preferably, the sample can be mixed by exerting an oscillating externalpressure to the blister. For example, a plunger or plurality of platensor plungers may be actuated against the first wall of the blisterthereby repeatedly displacing the sample contained within the blisterand causing its mixing. Similarly, the sample may be moved to differentregions within the blister by the application of pressure to the blisterthat effectively squeezes the sample to different regions of theblister. This may be advantageous where a liquid sample is required tobe moved to a different portion of the blister.

Advantageously a device according to the invention may further comprisean analysis means. It may be important that the sample is not removedfrom the device, even after processing, as this may contaminate theenvironment in the vicinity of the processing station using the device.In such a case it is particularly advantageous to have an analysis meanslocated within the device. Such an analysis means could be locatedwithin a temporary sealable region of the blister or it could be locatedin a separate analysis chamber that is in communication with theblister, for example via an exit port from the blister.

Preferably the analysis means is a test strip that contacts the sampleand produces a visual result. Thus, it is preferable that the analysismeans is located in a portion of the device that is at least in parttransparent such that the analysis can be determined optically orvisually.

The invention may have particular application to a device for theprocessing of a biological sample and particularly to a device for theamplification and detection of nucleic acid in a biological sample. Thedevice could, however, be used for processing other samples, forinstance environmental or chemical samples.

The invention may also provide a machine for automatically processingthe sample in a device according to any aspect described above. Themachine comprises a bay or slot for receiving the device and a tool orplaten for applying a localised external pressure to the device whenloaded in the machine. Preferably the machine has a plurality of toolsor platens adapted to interact with the device, and iscomputer-controlled to operate the tools or platens so that apredetermined sample processing protocol can be reliably and repeatablyperformed.

As many processing protocols involve incubation steps it may beadvantageous for the machine to further comprise a heater for applyingheat to a device. Particularly advantageously the heater may be part ofa tool or platen for interacting with the blister of the device. As analternative, a portion of the bay or chamber for receiving the device orthe entire bay for receiving the device may be heated and, thus, able toact as an incubator. It may be advantageous for the bay to act as anincubator and for one or more platens to be heated. This combination mayallow the temperature of the sample to be controlled within finetolerances.

Processing protocols may also require cooling stages or steps or thetemperature may need to be swiftly lowered in a particular protocol and,consequently, a cooler may be provided. Advantageously, a tool or platenfor interacting with the blister may be cooled, for example by acompressible gas, or may comprise a cooling means. For example, a toolor platen may have cooling channels for removing heat from the blistervia a cooling liquid or a cooling gas to lower the temperature of thecooled sample, or a tool or platen may comprise a thermoelectric coolingmeans, for example a Peltier cooler.

Where cooling is required, the bay or chamber may also be cooled as analternative to or in addition to cooling of platens.

The machine may comprise an actuatable platen that is substantially tubeshaped. Such a platen may be able to provide a two dimensional seal to aportion of the blister. Advantageously, the machine may comprise afurther platen independently actuatable within the tube shaped platenfor forming further sealed regions within an outer sealed region or forapplying an oscillating interaction for mixing a sample.

In a further aspect of the invention a system is provided for processinga sample comprising a device as described above and a machine forreceiving and manipulating the device. The machine comprises a platenfor applying pressure to the first wall of the device to create a seal.

Preferably the system includes a machine having one or more platens thatcan be independently operated to close and open seals in a predeterminedsequence.

The invention may also provide a method of processing a sample in adevice having a blister formed between a first wall and a second wall.In a preferred method the first wall is flexible and the methodcomprises the steps of applying a localised external pressure to urge aportion of the first wall towards the second wall to form first andsecond sealed regions within the blister, introducing a liquid sample tothe first sealed region, and removing the localised pressure to open theseal between the first and second sealed regions.

Preferably the blister is preloaded with dried reagents held atpredetermined locations and the external pressure is applied such that afirst reagent is located in the first sealed region and a second reagentis located in the second sealed region. For example, the localisedexternal pressure may form a seal that separates a region of the blisterin which a first reagent is located and a region of the blister in whicha second reagent is located, the two reagents then being in twotemporarily sealed regions within the device. Blisters may hold morethan one reagent, depending on the processing protocol required.

Typical processing steps such as incubation, heating or mixing may occurin the first sealed region before opening the seal between the first andsecond sealed regions. Likewise, where there are more than two sealedregions formed in the device, processing steps that are typical forprocessing a sample may be performed in each region prior to opening aseal and allowing communication of that region with the next sealedregion. Typically, each sealed region will contain a processing reagent,or will isolate an entry or an exit port, if present.

A preferred method of applying the localised external pressure is to usea shaped platen or tool that is actuated by a machine. The shaped platenmay be shaped to apply a pressure across the width of the blisterthereby dividing it by forming a seal across the blister's width.Preferably the platen will apply a pressure in the form of atwo-dimensional shape, for example a circle, to the blister to form asealed region in that shape, i.e. a sealed region with a boundary orperimeter having that two-dimensional shape. It may be possible to formsealed regions within other sealed regions by the application of platensthat are located inside other, hollow or tubular, platens. For examplethe platens may be a series of concentric tubes that apply pressure in aseries of concentric circles to the blister, thereby producing a firstsealed region that is entirely located within a second sealed region.

Preferably more than two sealed regions are formable within the blisteras this allows more reagents to be individually located and more complexprocessing protocols to be applied to the sample. A plurality of toolsor platens can be used to apply external pressure to form more than twosealed regions within the blister and preferably the seals separatingeach of the more than two sealed regions can be opened in sequence toallow the liquid sample to communicate with each region in predeterminedorder.

The method may include a mixing step and mixing may be advantageouslycarried out by oscillation of the tool or platen against the first wallof the blister.

Many processing protocols call for the use of liquid buffers or reagentsand preferably the device contains a liquid buffer or reagent containedin a sachet located within the blister. Preferably the liquid isreleasable by the application of an external pressure to the sachet. Thesachet may, therefore, have a frangible seal that is breakable upon apredetermined external pressure being applied.

The method may call for the movement of the sample within the blister,for example to contact different processing reagents or to move thesample out of the blister through an exit port. Preferably the movementwithin the blister is achieved by application of external pressure fromtools or platens.

The method is particularly applicable to performing a protocol on asample suitable for amplification of a nucleic acid.

Preferably, the method includes a further step of analysing the sample.Such analysis is preferably done after processing has been completed. Apreferred analysis method is to contact the processed sample with a teststrip that is located within the device, for example located within aseparate analysis chamber that is in communication with the blister. Anexit port allowing communication between the blister and an analysischamber may be isolated with a seal formed by the action of a tool orplaten until the sample is processed and the seal protecting the exitport is removed.

It may be advantageous to measure or select a predetermined volume ofliquid, for example to pass into an analysis chamber for analysis. Someprocessing or analysis steps may require that a defined volume ofliquid, for example a defined volume between 100 and 500 microliters, beused. Thus, the device may comprise a suitable means, or the method ofusing the device may comprise a suitable method step, for measuring orselecting such a volume of liquid for further processing or foranalysis.

A preferred moans of selecting a predetermined volume of liquid is toapply an external pressure to a portion of the blister containing theliquid sample, to form a seal that subdivides that portion of theblister and separates out the predetermined volume of liquid on one sideof the seal. The separated volume can then be passed to another regionof the blister or into an analysis chamber.

For example, this method may be used to select a predetermined volume ofa sample for processing. A larger volume of the sample may beintroduced, for example by injection from a syringe through a septum, tofill a metering portion of the blister that is preferably of elongateshape and bounded at one end by a first seal formed by an externalpressure. Once the metering portion of the blister is filled, a secondseal is formed, by application of an external pressure, at apredetermined distance from the first seal. The desired predeterminedvolume of the sample for processing is thus isolated within the portionof the blister between the first and second seals. The first seal canthan be released to allow the predetermined sample volume to flow into afurther portion of the blister for processing and analysis.

The method may also comprise a step of disposing of the device, it maybe important that the processed sample is not allowed to contaminate theregion around the test site so it may also be important that the useddevice is processed with an appropriate decontamination procedure priorto disposal.

Where the processing protocol involves amplification and detection ofnucleic acid if may be advantageous to perform a treatment to neutraliseprevious processing reactions or to deactivate amplified products toprevent priming of a new amplification reaction. If may, thus, beadvantageous to treat the device (for example a device according to anyembodiment or aspect described herein) and the used sample post-analysisto help prevent contamination of the point of use site. For example, tohelp prevent amplicon carry over contamination, the amplicon left in thedevice after a detection step could be treated with nucleic acidmodifying or hydrolysing agents that prevent priming of furtheramplification reactions. Decontamination may be particularly desirablewhere batches of samples are to be tested on the same site.

One such decontamination treatment described in U.S. Pat. No. 5,035,996involves incorporation into the amplified product of a ribo- ordeoxy-nucleoside triphosphate (rNTP or dNTP) base that is not generallyfound in the sample to be analysed, for example dUTP in the case of DNAanalysis. The amplified product will thus have a sequence that hasuracil in multiple positions. The enzyme uracil DNA glycosylate (UDG) isadded to the sample prior to amplification. This will cause enzymehydrolysis of any contaminating reaction product (containing uracil)without affecting the natural DNA in the sample.

Preferably decontamination is a chemical treatment or reagent that notonly modifies, but also degrades nucleic acid e.g. non-enzymaticdegradation of nucleic acid with chemical nucleases. Examples ofchemical nucleases are known in the art, e.g. divalent metal chelatecomplexes, such as copper phenantroline—Cu(II) or Ascorbate—Cu(II)cleavage as described by Sigman D. S. et al (J Bio Chem (1979) 254,12262-12282) and Chiou S. (J Biochem (1984) 96, 1307-1310).

A decontamination reagent could be conveniently delivered into theblister of the device after analysis of the sample for example byinjection through the sample introduction port. The device may,alternatively, be preloaded with both processing reagents and apost-analysis treatment or decontaminating reagent.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Embodiments of the invention will now be described by way of examplewith reference to the accompanying drawings in which:

FIG. 1 is an exploded view of a device according to an embodiment of theinvention;

FIG. 2 is a view of the device of FIG. 1 from the front and from theside showing the location of various reagents and ports;

FIG. 3 is a view of the device of FIG. 1 from the front and from theside, the side view showing the device as loaded into a machine withpressure seals being formed by tubular platens

FIG. 4 shows a front view and a side view of a sample being introducedinto a device according to FIG. 1;

FIG. 5 illustrates the introduction of a mixing/heating platen;

FIG. 6 illustrates the use of a mixing platen;

FIG. 7 illustrates the use of a mixing platen;

FIG. 8 illustrates the removal of a platen to allow the sample tocommunicate with a second reagent;

FIG. 9 illustrates the use of a platen to move the sample towards thesecond reagent;

FIG. 10 and FIG. 11 illustrate the use of a roller element to liberateliquid from a sachet; and

FIG. 12 illustrates the removal of a seal around an exit port allowingthe processed sample to contact an assay strip.

FIG. 13A illustrates a front view a device according to a secondembodiment of the invention.

FIG. 13B illustrates a side view of a device according to the secondembodiment of the invention.

FIG. 14 illustrates perspective views of a device according to theinvention.

FIG. 1 is an exploded view of a device embodying aspects of theinvention. The device 10 comprises a base moulding or base plate 20having a first side 21 and a second side 22 (not visible in FIG. 1). Thebase moulding is made of polypropylene but could be made of any suitablematerial, for example any substantially rigid polymer. A gasket 30 isfixed or formed, for example by overmoulding, on the first face 21 ofthe base plate. The gasket is made of a softer, more rubber like,polymer material than polypropylene, for instance, a thermoplasticelastomer (TPE) such as Dryflex® manufactured by VTC TPE Group orsimilar materials manufactured by companies such as Kralberg or PlasticTechnology Service Limited (PTS). The gasket is formed with depressions(31, 32 & 33) in order to locate objects within the device. The devicefurther comprises a flexible film 40 that is attached to the first faceof the base moulding and forms a blister 50 having the flexible film asa first wall and the base plate as a second wall. The blister 50 isformed with the gasket 30 substantially disposed inside the blister. Theflexible film may be any suitable film, for example a thermoformed filmhaving predetermined moisture and vapour barrier properties. A preferredexample of a suitable film is Aclar®. Aclar® is a trade name forpolychlorotrifluoroethylene (PCTFE).

A further example of a suitable film material is a polypropylene (PP)based flexible film such a TEKNIFLEX® MED 3014-0080. Such PP films maynot have the moisture protection properties as specialist films such asAclar® but may stretch and seal more effectively and be cheaper. Anyreduction in moisture protection provided by a flexible film can beovercome by sealing the device in a foil bag for transport and storage.

The flexible film has thermoformed dimples to locate objects within theblister.

The device further comprises an assay cover 60 that is fixed to the rearface of the plate and defines an assay chamber or analysis chamber 70.Both the interiors of the blister 50 and the assay chamber 70 are thussealed from the external environment. An exit port 100 defined throughthe base plate provides communication between the blister and the assaychamber.

The blister 50 has a plurality of location points defined by depressionsin the gasket and corresponding dimples in the flexible film forlocating reagents within the blister (for example at 51 & 52). Thedimples prevent the reagents from substantially shifting position withinthe blister, which at this stage is a single chamber.

FIG. 2 shows front and side projections of the device and illustratesthe locations within the device of a first freeze-dried reagent 200, asecond freeze-dried reagent 210, a third freeze-dried reagent 220, afourth freeze-dried reagent 230 and a liquid detection buffer containedwithin a sachet 240. The freeze-dried reagents and the sachet of liquidare located in the device during its manufacture and prior to theblister 50 being sealed. This advantageously avoids the need forhandling of reagents on site where sample processing is to be performedor the need to open the device on site, and may thus reduce thepotential for contamination.

As the film is flexible it is possible to apply an external pressureurging a portion of the film towards the base plate and against thegasket material thereby forming a localised seal. FIG. 3 shows front andside projections of the device and illustrates the position of threeseparate seals for producing sealed regions within the blister duringthe processing of a sample. The seal positions shown are an outer seal300 that bounds the first and second freeze-dried reagents, an innerseal 310 that bounds the second freeze-dried reagent thereby separatingit from the first freeze-dried reagent within the outer seal and anoutlet seal 320 that provides a seal around the exit port leading to theassay chamber.

The side view of FIG. 3 illustrates the device when loaded into amachine and also illustrates the use of two platens, first platen 400and second platen 410, to create the inner and outer seal. Both firstplaten 400 and second platen 410 are substantially tubular andseparately actuatable with second platen 410 being actuatable within thebore of the first platen 400.

The following steps describe the use of the device to perform a nucleicadd amplification and detection protocol.

Step 1; The device is loaded into a machine in a vertical direction forthe automatic processing of a sample as shown in the Figures and theseals (300, 310, 320) are applied to the blister by application ofexternal forces by a plurality of platens (400, 410, third platen notshown). See FIG. 3.

Step 2; A sample is introduced into the blister via an access port 110defined through the base plate; see FIG. 4. The access port may comprisea rubber septum and a syringe may therefore be used to introduce thesample.

Step 3; The liquid sample contacts and reacts with the first reagent 200(see FIG. 4). The mixture comprising the liquid sample and the firstreagent is prevented from accessing the third and fourth freeze-driedreagents by the seal formed by pressure exerted by the first platen 400,and from communicating with the second freeze-dried reagent by the sealformed by pressure exerted by the second platen 410.

Step 4; A mixing and heating platen or plunger 420 is introduced throughthe bore or lumen of the first platen as illustrated in FIG. 5. Mixingmay be affected by oscillation of the mixing/heating platen 420 as shownin FIGS. 6 and 7.

Step 5; The mixing/heating platen 420 is held over the blister incontact with the film in order to perform a heating and incubation stepof the processing protocol.

Step 6; After appropriate mixing, heating and incubation has beenperformed on the sample, the second platen 410 is removed allowing thesample to contact the second freeze-dried reagent; see FIG. 8.

Step 7; In order to force the liquid sample to contact the secondfreeze-dried reagent, the mixing/heating platen 420 is reintroduced andsqueezes the liquid sample into the region of the blister occupied bythe second freeze-dried reagent, (FIG. 9). Mixing may again occur byoscillation of the mixing/heating platen.

Step 8; A cam or roller 430 is applied to the blister in the region inwhich the sachet is located; see FIGS. 10 and 11. The cam or rollercauses a pressure to build against a frangible and of the sachet 241,causing the liquid to be liberated into the blister where it reacts withthe second and third freeze-dried reagents. This liberating pressure mayalternatively be applied by a reciprocating platen or plunger acting toapply pressure to the sachet.

Step 9; The first platen is removed to allow the sample to contactliquid liberated from the sachet. This is illustrated in FIG. 11.

Step 10; After any further mixing or processing (for example incubation)has occurred to produce a processed sample, the final seal 320 isremoved to allow the processed sample to enter the assay chamber 70where it contacts an assay strip 71; see FIG. 12, which shows front andrear projections of the device.

Step 11; The results of the test are visually shown by the assay stripthrough the assay cover.

Step 12; The device is removed from the machine and disposed of.

It should be clear that different protocols can be used in a deviceaccording to the invention. For example, either the first or the seconddried reagent may be omitted and, therefore, only the inner seal or onlythe outer seal from the above example need be formed. If only one suchseal is formed it could be circular, or oval, or any other suitabletwo-dimensional shape. FIG. 13A illustrates such a device in which onlytwo pressure seals are formed, the first 1300 defines a first sealedregion 1310 surrounding reagent 1305 within the device 1400, and thesecond 1320 forms a second sealed region 1330 surrounding an exit port.

FIG. 13B illustrates the device of FIG. 13A viewed from the side. Thisfigure illustrates a hinged cover 1410 that protects the front face 1405of the device during transit and handling. The hinged cover opens whenthe device is inserted into a processing machine.

FIG. 14 illustrates a further embodiment of a device according to theinvention. The device 1500 has a solid base-plate 1510 incorporating afinger grip 1515 for facilitating handling. A blister 1512 containingreagents is formed on the base-plate from a flexible material. Theblister is protected during transit and handling by a hinged cover 1520.The cover is connected to the base-plate at a hinge 1521 and is held inplace by snap-fit connections 1522 that engage with correspondingfeatures 1523 defined in the base-plate.

In a further embodiment of the invention the device may comprise avacuum port for withdrawing air from the blister prior to processing thesample. The vacuum port may comprise a rubber septum spanning a hole inthe base plate. If a vacuum is to be applied to a device it may beadvantageous to select a film for forming a wall of the blister that hassuitable barrier properties, for example a film that is substantiallygas impermeable.

The invention claimed is:
 1. A method of processing a sample in a devicehaving a single blister only, the blister defined between a first walland a second wall, in which at least the first wall is flexible suchthat the blister can be divided into one or more sealed chambers by anexternal pressure applied to a portion of the first wall that urges thefirst wall towards the second wall, the method comprising: applying alocalised external pressure in the form of a two dimensional shape tourge the first wall towards the second wall to form first and secondsealed chambers within the blister, introducing a liquid sample to thefirst sealed chamber, and removing the localised external pressure, sothat the blister becomes undivided, and to open the seal between thefirst and second sealed chambers.
 2. A method according to claim 1,further comprising: preloading the blister with dried reagents held atpredetermined locations and, after applying the localised externalpressure, a first reagent is located in the first sealed chamber and asecond reagent is located in the second sealed chamber.
 3. A methodaccording to claim 1, further comprising: incubating, heating or mixingin the first sealed chamber before the seal is opened between the firstand second sealed chambers.
 4. A method according to claim 1, whereinthe localised external pressure is applied by a shaped platen or tool.5. A method according to claim 1, wherein more than two sealed chambersare formable within the blister.
 6. A method according to claim 4,wherein a plurality of tools or platens are used to apply the localizedexternal pressure to form more than two sealed chambers within theblister.
 7. A method according to claim 5, further comprising: openingthe seals separating each of the more than two sealed chambers insequence to allow the sample to communicate with each chamber in orderas it is processed.
 8. A method according to claim 4, furthercomprising: mixing the sample by oscillation of the tool or platenagainst the first wall.
 9. A method according to claim 1, wherein thedevice contains a liquid buffer or reagent contained in a sachet that islocated in the blister, the liquid being releasable by the applicationof an external pressure to the sachet.
 10. A method according to claim1, wherein the sample is moveable within the blister by the applicationof an external pressure from a tool or platen.
 11. A method according toclaim 1, wherein the sample undergoes a protocol suitable foramplification of a nucleic acid or genetic material.
 12. A methodaccording to claim 1 further comprising: analysing a sample processed bythe method.
 13. A method according to claim 12, wherein, the analysingcomprises: contacting the processed sample with a test strip locatedwithin the device.
 14. A method according to claim 1, furthercomprising: loading the device into a machine for automaticallyperforming processing on the sample.
 15. A method according to claim 14further comprising: removing the device containing a sample processed bythe method from the machine; and disposing of the sample.
 16. A methodaccording to claim 1, further comprising: decontaminating the device.17. A method according to claim 1, wherein an external pressure isapplied to a portion of the first wall to isolate or separate apredetermined volume of liquid within the blister.
 18. A methodaccording to claim 1, further comprising: applying a vacuum to theblister to facilitate introduction of the sample and/or transfer ofliquid within the device and/or mixing of reagents and the sample and/orsealing portions of the device and/or locating objects within thedevice.
 19. A method according to claim 1 in which the blister is sealedfrom the external environment.